Combine a Trombe Wall with a TEC. https://en.wikipedia.org/wiki/Trombe_wall https://en.wikipedia.org/wiki/Trombe_wall https://en.wikipedia.org/wiki/Thermoelec

Combine a Trombe Wall with a TEC. https://en.wikipedia.org/wiki/Trombe_wall https://en.wikipedia.org/wiki/Trombe_wall https://en.wikipedia.org/wiki/Thermoelectric_cooling https://en.wikipedia.org/wiki/Thermoelectric_cooling I don't think it would make much electricity. But a Trombe wall can trap a huge amount of heat.